Loading ...
Sorry, an error occurred while loading the content.

1125AI-GEOSTATS: Summary: Log-normal back transform in Webster & Oliver]

Expand Messages
  • Gregoire Dubois
    Jul 29, 2003
    • 0 Attachment
      Hello again,

      Murray's reply to my question says it all. Thanks again a lot to Isobel Clark
      (special thanks for the nice explanation on the behaviour of the Lagrange
      parameter !), Gerard Heuvelink and Murray Lark.


      ------ Original Message ------
      Received: Mon, 28 Jul 2003 06:22:12 PM CEST
      From: "murray lark (SRI)" <murray.lark@...>
      To: 'Gregoire Dubois' <gregoire.dubois@...>
      Subject: RE: AI-GEOSTATS: Log-normal back transform in Webster & Oliver


      Just to follow up my previous email, I have had a word with Dick Webster who
      confirms that the missing Lagrange multiplier in Equation 8.38 was a printing
      error, he thanks you for pointing it out. Also note that the Lagrange
      multiplier should have an argument, bold x_0, since it is specific to the
      kriging target site.

      Murray Lark

      -----Original Message-----
      From: Gregoire Dubois [mailto:gregoire.dubois@...]
      Sent: 28 July 2003 10:39
      To: ai-geostats@...
      Subject: AI-GEOSTATS: Log-normal back transform in Webster & Oliver

      In the book "Geostatistics for Environmental Scientists"
      By Richard Webster & Margaret A. Oliver, Wiley (2000), one will find in page
      180 a brief discussion on the back-transformation of the kriging estimates.

      In ordinary kriging, when the natural logarithm (ln) is used, the
      back-transformation will involve the Lagrange parameter (see equation 8.36).
      No problem so far.

      But... the authors write in equation 8.38 that if one is using common
      logarithms (log10) instead, the unbiased back-transformation of the ordinary
      kriging estimates does not involve the Lagrange multiplier anymore.
      Is this correct ? In the affirmative, can someone point me to a paper
      discussing "natural" log normal kriging versus "common" log normal kriging ?

      Thanks again for any help.



      * To post a message to the list, send it to ai-geostats@...
      * As a general service to the users, please remember to post a summary of any useful responses to your questions.
      * To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list
      * Support to the list is provided at http://www.ai-geostats.org